The present invention relates to a novel and useful accommodating intraocular lens.
Intraocular lenses have been implanted in eyes following cataract surgery for a number of years. A conventional intraocular lens is intended to replace the natural lens which has been removed due to such cataract condition. Surgical techniques have evolved over the years to performance of an extra-capsular procedure. That is to say, the capsule which held the removed natural lens is retained in the posterior chamber of the eye, minus an excised frontal portion. The result is a capsular bag connected to the ciliary muscle by a multiplicity of zonules, commonly referred to as the zonular system. In this manner, vitreous humor is maintained in the posterior chamber of the eye and the inserted intraocular lens is confined or fixed in the eye for use.
Unfortunately, intraocular lenses do not provide the patient with near and far vision, since intraocular lenses do not react to the contraction and relaxation of the zonular system. This ability is normally referred to as “accommodation”. Thus, a patient must be fitted with corrective glasses in order to perform tasks associated with near and far vision, e.g. reading and driving a vehicle.
In the past, accommodating intraocular lenses have been proposed, but have gained limited success.
For example, U.S. Pat. Nos. 4,485,499 and 6,200,343 B1 show intraocular lenses with resilient curved open loops to fix and intraocular lens in the posterior chamber of the eye.
International patent application WO 92/15260 reveals an intraocular lens with a pair of loops that essentially encircle the lens to aid in the fixation of the same to the posterior chamber of the eye when compressed.
U.S. Pat. No. 5,133,750 shows an intraocular lens constructed of synthetic sapphire which includes a quartet of arms to hold the lens in place.
International application WO 01/0532782 describes an intraocular lens for pediatric use which employs a pair of curved arms that completely encircle the lens to prevent the formation of a secondary cataract.
U.S. Pat. No. 5,571,177 indicates an intraocular lens with a fixation member that can be altered after insertion to control the repositioning of the optic portion of the eye.
U.S. Pat. No. 5,628,798 teaches an adjustable and removable intraocular lens having a portion which may be changed, adjusted, or modified after insertion.
U.S. Pat. No. 6,117,171 illustrates an encapsulated accommodating intraocular lens having two spaces separated by a transparent flexible membrane. Altering the curvature of the membrane alters the overall optical power of the lens.
U.S. Pat. No. 4,888,012 shows an intraocular lens assembly in which the lens is formed of elastic material which is extended or compressed to change the shape of the optical portion to accommodate with alterations in the tension of the ciliary muscle of the eye.
U.S. Pat. No. 6,176,878 B1 poses an accommodating intraocular lens having an optic that is connected to a flexible disc that moves the optic inwardly and outwardly according to changes in the tension of the ciliary muscle.
U.S. Pat. Nos. 4,409,691, 4,994,082, 5,476,514, 6,179,870 B1, and publication U.S. 2001/0016771 A1 describe accommodating intraocular lens structures which employ flexible arms that move the optical portion of an intraocular lens posteriorly or anteriorly with ciliary muscle changes and tension.
An optically accurate accommodating intraocular lens would be a notable advance in the medical field of eye care.